I was using a NON-threading compression tester to check compression on LT80. The type with the rubber boot that you try to wedge in the spark plug hole. Got readings of 60-80lbs. Squirted in a little WD40 and it jumped to 100-110. Does this sound correct?Time for rings?Does anyone trust these old testers, and how far out could it be? I'm told they're good, they're just old technology.

 

BTW, it's a 93 that had been sitting for quite awhile and was badly neglected by previous owner.After cleaning carb, fixing starter,cleaning airbox, it wouldn't start of fire. Tried pouring a little gas straight into cylinder, no fire. Spark seems very strong when plug grounded on engine. So if it walks like a duck...(?)

 

You don't have enough compression to get it started. It is time to rebuild.

 

asfasasu3 is correct, I'm pretty sure in a 2 stroke, you will need at least 100 - 110 psi just to run, check the cylinder,if it isn't all scratched up,you may just have bad rings and can get by with a stock piston and rings, otherwise, a .010 bore will put you back into the running.

 

I guess if you bore, you need a different piston and oversize rings?(i.e-I can't get this from Suzuki?)

 

Yes you would need new piston and rings if you bore it. A dealer should be able to get the oversize parts for you. They may be higher in price than if you were to order through someone else though. I geuss I'm pretty lucky, I've got a great little shop near my home that gives me great deals on parts like this. Our lt would start with 90 lbs when cold, after it warmed up it would not run at all, let alone start. (I believe it's supposed to have around 110lbs) You can do a search on here or wait till Jack (aka. lt80) gets back and he can help you out probably more than anyone.

One more thing. By all means get the piston and rings BEFORE you have a shop bore it. Have them bore the jug to match the piston (with tolerances of corse) Most machine shops will do this with no problems, pistons have been know to vary in size. Alittle big on the tolerances and a piston that is a little small on its tolerances, and you could have more problems.

 

I seem to recall Jack said in another post you should have minimum 160lbs. I was more curious if my readings could be way out because of the type of tester I'm using. It would make sense that this is my weak link since it's not starting at all.

This unit still has original tires and was neglected but hard to know if it was also abused. I'm hoping just rings. Before I tried starting it I removed fan cover and sprayed a little penetrating fluid in cylinder. Did this a couple of times and waited a day or 2. The fan was a little stiff to turn and then it turned over quite easily. When I described this to someone else, they thought I might have broken a ring getting it freed up. Guess I'm being lazy and should pull the head, check ring gap, then cylinder.

I really wish I had an alternative to Suzuki dealer for parts. My dealer is great but I'm getting tired of Suzuki not kissing me after they're done with me. Prices hurt. $58 for a simple plastic gas cap??I'll bet rings, head and cylinder gasket cost $60-80. What type of shop sells parts for these (other than dealer)?We have a local small engine repair place, but they're horrble to deal with. Probably lots of stuff available on-line, but by the time I convert $$, plus tax and duty, I might aswell go to suzuki.

 

btw, the Suzuki manual gives the compression ratio, but i can't find a spec anywhere about what you should get for a comprsssion test reading.

 

check ebay, lots of stock and aftermarket parts, even aluminum wheels and tires, you might even find a nice rebuild kit with everything you need, a lot cheaper than the dealer.

 

yep, you guys were right. pulled cylinder today. checked end gap for rings first and they were like new based on the specs (.018), limit is .031. thought wtf, it's perfect. looked at piston and it was badly scored, directly in line with the arrow/exhaust port.Outside edge of ring also scored. I wonder if a little piece of crud or rust broke off from exhaust pipe or gasket somehow. don't matter, ordered replacement piston, rings and circlips- about $45-50 (USF).I don't think I'd find it for much cheaper?? Bore will cost me $30 (US). head gasket seemed fine. would anybody reuse, or would you replace? cylinder gasket has a little nick between headbolt and crank, so I better replace that, or it will be a weak spot.

awfully rusty in there. don't want to split case, so I tried cleaning and blowing it out with compressed air as best I could. Does reed valve need service generally? it seems a little rusty too.